Printing telegraph system



i o I Y I Sept d w27 G. s. VERNAM x-:T AL,

' PRINTING TELEGRAPH SYSTEM `Patented Sept. 13, 1,927.

UNITED STATES PATENT orti-"ICE,

GILBERT s. VEENAM, or'nIvER EDGE, NEW JERSEY, AND DONALD E. TERRY, or

YQNKERS, NEW YORK, ASSIGNORS TO AMERICAN T TELEPHONE AND' TELEGRAPH COMPANY, A CORPORATION OF NEW YORK.

PRINTING TELEGRAPH SYSTEM.

application inea November es, 1925. serial No. 71,978.

This inventionrelates to printingl telegraph exchange systems and more especially to such systems wherein switching means are employed for establishing and controlling communication circuits between separated stations.' y

An object of the invention is to improve printing telegraph systemsby incorporating thereineiiicient and reliable switching and A 1D power .control apparatus.

A feature of the invention ,contemplatesa printing telegraph system wherein there area plurality of central or main stations and a plurality of substations.

A further feature of the invention relates to a printing telegraph system whereina communication circuit is established and printer driving motors are controlled `by means ofa manually operated switch.

Other features and advantages inherent in the invention, while not specifically enumerated, vwill become apparent'upon'a consideration of the following description'and upon consideration of the appended claims. v The invention'is disclosed asapplied to a printing telegraph system wherein a power source is provided at each station for driving the sending and receiving apparatus thereat. sThe power source is arranged to be 30 normally disconnected from the printing apparatus and is adapted to be rendered effective by remote control, i. e., as a result of aswitching operation at a distant point.y -This switchingoperation is effective not only 'to control the powersource but also to selectively establish a printing communication circuit as will be described hereinafter.

The drawing illustrates the invention in connection with a center radial switching system with a plurality of outlying stations. The central stations may call and communicate with each other'and with any of the outlying stations. Any out station-may signal either of the central st atiorls` to notify said station that communication is desired. Busy' signals for the substation are provided at the central stations for notification when such substations are in communication with the other central stations. v f

-Referring to the drawing there are shown in the upper portion of the iigure' within the dotted rectangles two substations. The central portion of this figure discloses a first central station, and thev lower portion` 'dis-l the conductorsof this loop is used for concloses a second central-station. Eacli of the 55 substations is provided with the usual transmitting and receiving telegraph printing apparatus and in addition there are provided a number of manually operable keys by means of whichthe substations may signal either of the central stations. The power source for the printer, shown schematically, is normally disconnected from the Aprinting apparatus by means of the contacts of a special control relay which is normally operated, and is released upon the establishment of a' printing telegraph circuit. There are provided a number of keys at the central station one for each central station and one for each substation. Each central station may be provided with a plurality ofv printer sets 25 and 26. It will be noted that each substation is connected with the central station by means of a two conductor loop. One ot' trolling the signal and power circuit while the other conductor is used for the printing telegraph communication circuit.

It is believed that a better understanding of the preferred formv of carrying out the invention may be had from a detailed flescription of the. mannerl in which the circuits are established, first between cent1-al stations, and second between central stations and 'substations tion No. l desires to send a printed' message to the central station No. 2. It will be noted 90' that "relay 29, which controls the association of the power source 27 with the driving motor 28, is held normally energized over a circuitl traceable from groundthroughthe winding of said relay, lower left make-before- 9J break contacts-9f key 2, lower make-beforebreak contacts `of keys 7 and 8, lower right normally closed contacts of key 2, to battery through the winding of linerelay 31 assoeiated with printer set 525. In like manner a circuit may be traced-for maintaining energized control relay v1 associated with printer 26 over a circuit comprising corresponding'upper contacts of keys 2, 7 and 8, and the winding of line relay 9. Let it be assumed that the operattir at station No. l desires to use the printer set shown within the dotted rectangle 2,5. Tle operator manipulates key to its' downward position whereupon a circuit may be traced 'from ground through the winding of relay 29, lower left make-before-break contacts of key 2, resistance 3, upper left normally closed contacts of key 4 at central station No. 2, lower left normally closed contacts of key 4, lamp 5, resistance 6, to grounded battery. By means of the inake-before-break arrangeincnt of the lett hand contacts of key 2, this latter traced kcircuit is closed before the original circuit for energizing relay 29 is broken, consequently relay 29 remains en' ergized and lamp 5 is lighted, The lighting of lamp 5 attracts the attention of the operator at station No. 2. Assuming that theoperator at this station desires to use the printer shown within the dotted rectangle 32, the key 4 is operated to its upper position thus opening the circuit for lamp 5 which is thereby extinguished. The control relay 19 associated with printer set 32 was normally energized over a circuit traceable from ground through the windin of said relay, upper left make-beforebrea contact of key 4, upper inake-before-break contacts of keys and 14, winding of relay 34 to battery 67 through upper right contacts of key 4. When the operator at station No. 2 manipulates key 4 as above described, the circuit for energizing relay 10 is transferred to conductor 51 whereby relay 10 is connected in series with relay 29 and both of these relays thereupon release. Relay 29 upon releasing operatively connects, by means of its back contacts, the power source 27 with the printer driving motor 28. In a similar manner relay 10 completes the circuit from the power source 35 to the motor 36. The -printing communication circuit may now be traced from battery through the winding of line relay 31, transmitting device TR, lower right make contacts of key 2, resistance 12, upper right make-before-break contacts of key 4, transmitter TR, Winding of line relay 34, make-beforebreak contactsof keys 14 and 15, to round through upper left make contacts of ey 4. Relays 31 and 34 respond to the transmission of the telel graph impulses and correspondingly control the respective printer magnets 37 and 38 whereby the printer impulses are translated and recorded on the receiving printers. When communication is completed, the keys 2 and 4 are restored to normal resulting in the closure of the circuits for relays 29 -and 10 as hereinbefore described, causing the motors 28 and 3 6 to come to rest. Should the call originate from central station No.l 2, key 4 is yoperated causing the lighting of call lamp 17 at central station No. 1 over a circuit traceable from battery through said lamp, upper left normally closed contacts of key 2, lower left normally closed contacts of said key, resistance 3, upper left accanita normally closed contacts of key 4, lower left make-botore-break contacts of key 4 (assuming printer sct'39 yto be used) to ground through the winding of control relay 18.

The operator at station 2 upon noticing the lamp 17 operates key 2 to one position or Uommmmlcatc'ou between, a substation and the first @effi-trol station.

It will now be assumed that the subscriber at. the substation 60 desires to communicate with central ofiice No. 1. This is effected by operating key 47. It will be noted that normally a circuit may be traced from ground through the winding of printer magnet 43, contacts of the associated transmitter TR, contacts of key 47, resistance 44, right nor mally closed contacts of key 8, winding of relay 46, right normally closed contacts of y key 14 to grounded battery. Relay 46 is maintained energized in this circuit. Another circuit is normally closed'for holding operated control relay 48. This circuit may be traced from ground through the Winding of control relay 48, winding of relay 49,

resistances53 and 54, left normally closedl contacts of key 8, winding of relay 45, left normally closed contacts of'key 14, windin of relay 55, upper or operating winding o polarized relay 56 togrounded battery. The

Vcurrent in this circuit is insufficient to overcome the lower or biasing Winding and operate relay 56. The operation of key 47 as above mentioned opens the circuit for relay 46 but relay 45 remains energized. Consequently, the release of relay 46 completes an obvious circuit for lighting call lamp 57.`

Assuming that printer 25 at central station No. 1 is to be used, the operator upon noticing the lighting of lamp 57 operates key 8 to close the lower set of contacts. The opening of the lower left hand contacts of key 8 breaks the circuit including the windings of relays 48, 49, 45 55 and 56. Relays 48, 49, 45 and 55 therefore release at this time. Relay 55 in releasing completes an obvious circuit for lighting busy lamp 58 to notify the operator at central station No. 2 that the substation :#:60 is in communication with central station No. 1. Relay 45 in releasing opens the circuit for line lamp 57 and closes the circuit for lighting busy lam 59 at central oice No. 1. At its right han contacts relay 45 also shunts relay 46 to reduce the resistance of the printing circuit. By means of the opening of the right hand contacts of key 8, the circuit for, normally maintaining 3" anl increase of current through the circuit motor 28. The motor 62 at station 60 is operatively connected with power source 63 by means -of the back contact of relay 48, -when this-rela releases as described hereinabove. Both t ve lmotor at the substation and at the centi'al station* are thus in operation.

The printing communication circuit may therefore be traced from battery through the winding of 'line relay 31, contacts of assolo ciated transmitter TR, right lower normally closed contacts of key 2, right lower makebeoi'e-breakcontacts of key 8, right upper normally closed contacts of key 8,- resistance 44,'back contacts o f relay 49, transmitter TR vl5A to ground through the winding of the printer ,magnet 43. l-hen the communication is completed theoperator at central station No.

1 restores key 8 to normal thus operating control relays 48 and 29 whereby vmotors 28 2o and 62 are stopped. The call key 47 at the substatiomif not already restored, may be 'restoredat this time.

@ammum'ctz'on between a sabstiation'rand the second central station.

Should the subscriber of station 60 desire to Vcommunicate with central station No. 2 key 64 is operated. lrVhen key 64 is operated, resistance 53 is short-circuited resulting in comprising the windings of relays 48, 49, 45, .5 5 `and56' as hereinbefore described. This increase of, current is suiiicient to cause the armature of .polar relay 56 to move to itsl frontmarking contactr'esulting in the lighting'of call lamp 65 over an obvious circuit. Should theoperator at central station No. 2 desire to use printer 32, key 14 is operated to close its upper contacts. The'opening of the' 40 upper contacts of key 14 causes the release of relays 48, 49, 45, 55 and 56 as hereinbefore.

described. Relay by means of its right contacts short-circuits thewinding of rela-y 46 to prevent this relay from following the H45 printing impulses, and by means of its 'left contacts opens the circuit of line lamp 57 `and lights-.busy lamp 59. The closure. of the power circuits at the substation and at the central oilice is controlled in a manner iden- 50 tical with that already described in connection with'central station No. 1. The printing` joircuitmay therefore be traced from battery 67 upper right normally closed contacts of key 4, transmitterTR 'winding of line relay 34, upper right 'make-before-b'reak contacts of key 14, back contact of relay 45, right 'normally closed contacts of key 8, resistance y44, back contacts of relay 49, to ground through the transmitter TR and the-printer magnet 43. When communication is completed, tlisestablishment of communication is under control of the central oiiice operator by means of the release of key 14. f

.- When the operator at a central station,

nior example, station #2,- desires to communicate with a substation as substation #60, the corresponding key 14 is operated.-

This breaks the normally closed circuit including the windings of relays 48, 49, 45,

5'5-and 56.- Relay 55 in releasing causes the busy lamp58 to be lighted, and similarly.

relay 45 closes a circuit Afor busyX lamp 59.

If key 14l is operated to close the upper fset;

of contacts, the control relay 10 .for printer set 32 is released. With relays 48- and.10 i released, the corresponding motors 62 andl 36 are started in operation, andthe printercircuits are completed in the manner here-A inabove describe i p While in the foregoing description two derstood that others may be-provided as required. In this case corresponding switchl ing keys similar to keysf 7 and 8 are provided at the respective central offices. Likewise the circuits for the motorlcontrol substationshave been shown, it will be n n-- relays may be normally-opened and Ythe association of the power SourCesvvith" the` rality fof centralstations, a pluralit "of f substations, printing telegraph receiving and transmitting equipment atv each station,

and switching means at each substation Jfor selectively establishing a printing telegraph communication circuit with any of said 2. In a .printinnf'l telegraph system a plurality of centralfsltations, a. lurality of s ubico stations', printing telegrap rreceiving and transmitting equipment at each station,

1 switching meansat each central station for 'completing a communication circuit to any of, .they other central stations, and other vswitching.'means at each central station for `completing a communication circuit with any pof said substations.

3. In aprinting telegraph'system, a plurality of Acentral stations, a plurality of substations, printing telegraph receivingand transmittingequipment at each station,

a plurality of calling vkeys at each substation one key for each central station, and switches at each central station adapted to be operatedv in response. to the operation of one ofsaid calling keys to complete aprinting telegraph communication circuit between va central oiice and thel substation wherein said one of said. calling keys is 4:, a printing telegraph 'system, the

combinationof a plurality of central,y stations, al plurality of substationsfa plurality roit keys at each central stationv adapted to callv any substation and to complete acom- :mu'nication circuit therewith,` anfdj aiiotlierf-I plurality gt keys at each central' station means therefor at each station said driving means being normally inert, and two conductor loops extending between each substation and said central stations, one of said conductors being used to control the opera* tion of the motors atthe central station and the substations, the other of said conductors being used for the printing telegraph communication circuit.

6. In a printing telegraph system, central stations, a plurality of substations, a print-- ing telegra Jh receiving and transmitting set at each su station, a plurality of printing telegraph receiving and transmitting sets at each central station, a plurality of answering keys at each central station, one for each substation and adapted when operated to associate any of the transmitting and receiving sets at the central station with a calling substation.

7. In a printing telegraph system, a substation, a plurality of central stations, a

signal and motor control wire extending from said substation through one of said central stations to another of said central stations, a calling key at each substation associated with said wire, and means operative when said key is actuated to effect a calling 'signal atene central olice and to effect a busy signal at the other .central office.

8. In a printing telegraph system, 'a plu rality of substations, printing telegraph transmitting and receiving equipment and a driving'motor therefor at each substation, a plurality of central stations, an operators position at each central station, and a plurality of switches at each operators position for controlling the operation of the printer driving motors at the central stations and the substations and for controlling theestablishment of printing communication circuits.

In testimony whereof, We have signed our names to this specification this 27th day of November, 1925.

GILBERT s. VERNAM. DONALD e. PERRY. 

